From the moment a baby enters the world, the nervous system is already performing an extraordinary number of tasks.

Touch a newborn’s cheek and the baby instinctively turns toward the stimulus. Place a finger in the baby’s palm and tiny fingers automatically close around it. Introduce a sudden movement or noise and the arms rapidly extend before drawing back toward the body.

Nobody teaches a newborn to perform these movements.

They are primitive reflexes—automatic responses built into the developing nervous system.

These reflexes play an essential role during the earliest stages of life. But something equally important must eventually happen: as the brain matures, voluntary control gradually takes over.

Understanding that transition provides a fascinating window into human brain development and can also give clinicians important information about nervous system function.

At Hope Brain & Body Recovery Center, neurological assessment looks beyond symptoms alone to understand how different areas and pathways of the nervous system are functioning and communicating.

What Is a Reflex?

A reflex is a stereotyped, automatic motor response triggered by a particular stimulus.

Unlike voluntary movement, you don’t consciously decide to perform a reflex.

The response happens rapidly and predictably because many basic reflex pathways are mediated primarily through the brainstem and spinal cord, rather than requiring the higher cerebral cortex to consciously process the situation first.

This speed has an important biological purpose.

Some reflexes help protect us from danger. Others support feeding, posture and movement. During infancy, primitive reflexes help a newborn interact with the environment before the higher brain has developed sufficient control for sophisticated voluntary movement.

Three characteristics make these early reflexes particularly important:

They are automatic. The infant does not consciously decide to perform them.

They are primarily subcortical. The responses rely heavily on lower neurological centers, including the brainstem and spinal cord.

They are foundational. They support survival and early physical development while more advanced neural networks continue to mature.

What Are Primitive Reflexes?

Primitive reflexes begin developing before birth and are present during the newborn period.

They essentially provide the developing nervous system with an automatic starter kit.

Before a baby can intentionally reach, grasp, roll, crawl, sit or walk, primitive reflexes help create early patterns of sensory and motor activity.

Some of the best-known primitive reflexes include the Moro reflex, rooting reflex, palmar grasp and Asymmetric Tonic Neck Reflex (ATNR).

The Moro Reflex: The Early Startle Response

The Moro reflex is an automatic response to sudden movement, loss of support or unexpected sensory stimulation.

The infant typically extends the arms before drawing them back toward the body.

It is essentially an early protective response.

The movement happens automatically because the infant’s nervous system does not yet possess the mature cortical control that will eventually allow more sophisticated responses to unexpected events.

The Rooting Reflex: Helping a Baby Find Food

Gently touch a newborn’s cheek and the baby will often turn the head toward the stimulus while opening the mouth.

This is the rooting reflex.

Its purpose is highly practical: it helps a newborn locate and latch onto a feeding source.

Before the infant can consciously understand where food is coming from, the nervous system already has an automatic mechanism designed to help make feeding possible.

The Palmar Grasp Reflex

Place a finger or small object into a newborn’s palm and the baby’s fingers will automatically close around it.

This is the palmar grasp reflex.

Over time, automatic grasping gives way to intentional reaching and gripping.

Eventually, that child may use the same hand to hold a spoon, throw a ball, draw a picture, write their name or play a musical instrument.

The progression beautifully demonstrates how the nervous system moves from automatic response toward purposeful control.

The Asymmetric Tonic Neck Reflex

The Asymmetric Tonic Neck Reflex, or ATNR, is another important early sensorimotor pattern.

When the infant’s head turns toward one side, the limbs on that side tend to extend.

This early relationship between head position and limb movement contributes to the developing sensorimotor system.

As neurological development progresses, however, the child must eventually be able to move the head, arms and legs independently rather than remaining controlled by this automatic pattern.

And that brings us to one of the most important stages of early brain development.

From Reflexes to Voluntary Control

Primitive reflexes aren’t meant to dominate movement forever.

As the nervous system matures, the cerebral cortex gradually gains greater control over lower neurological centers.

This increasing top-down influence allows the brain to inhibit primitive responses and replace them with increasingly sophisticated voluntary movement.

The presentation describes this progression in three broad stages:

In utero: Primitive reflexes emerge and are active around birth.

0–6 months: Cortical maturation progresses and voluntary movements increasingly appear alongside reflexive patterns.

6–12 months: Many primitive reflexes become inhibited or integrated as cortical control develops.

Rather than thinking of these reflexes as simply “disappearing,” it can be helpful to think of them as becoming integrated into a more mature nervous system.

The child is moving from automatic survival toward intentional control.

Why Reflex Integration Matters

This neurological transition provides the foundation for increasingly complex movement.

As cortical control develops, a child becomes better able to intentionally control the head, trunk and limbs.

Those abilities contribute to later skills involving:

• Posture
• Balance
• Coordination
• Reaching
• Grasping
• Crawling
• Walking
• Fine motor control

Early sensorimotor development also occurs alongside rapidly developing cognitive and sensory systems.

This is why reflex development can provide clinicians with useful information about the overall maturation of the nervous system.

Hope Brain & Body Recovery Center works with children experiencing neurological and developmental challenges through its Neurodevelopmental Disorders program, where evaluation considers medical health, cognitive function and behavior when developing an individualized treatment strategy.

What Are Retained Primitive Reflexes?

Sometimes a primitive reflex remains observable beyond the developmental period when it would normally become integrated.

This is commonly described as a retained primitive reflex.

The presentation describes retained reflexes as potentially competing with voluntary control and affecting areas such as posture, coordination and balance.

It also identifies possible associations with difficulties involving attention, sensory processing and academic skills such as reading and writing.

Importantly, a retained reflex is not by itself a diagnosis of ADHD, autism, dyslexia or another neurodevelopmental disorder.

Rather, abnormal reflex findings can form one part of a broader neurological and developmental assessment.

This distinction matters.

A child struggling academically or behaviorally should not be reduced to one reflex test. The goal is to understand the broader pattern of neurological, sensory, cognitive and developmental function.

Hope Brain’s article on Neurodevelopmental Disorders and Optimizing Brain Functionality explains more about its approach to assessing sensory and neurological patterns associated with developmental difficulties.

Reflexes Can Be Neurological Red Flags

Clinicians don’t only look for whether a reflex is present.

They also consider when it appears, whether it is symmetrical, when it should become integrated and whether it later reappears unexpectedly.

Several patterns may deserve further investigation.

Asymmetry

A reflex that responds differently on the left and right sides may provide information about asymmetric neurological function and, depending on the reflex and clinical context, may warrant further assessment.

Persistence

A primitive reflex that continues substantially beyond its expected developmental period may indicate that neurological maturation deserves closer evaluation.

Absence

The absence of an expected reflex can also be significant and may point toward problems affecting peripheral nerves, lower motor neurons or other portions of the nervous system.

The key point is that reflexes provide clinicians with another window into nervous system integrity.

What Happens When Primitive Reflexes Appear in Adults?

This is where the subject becomes particularly fascinating.

Primitive reflex patterns that are normal during infancy are generally suppressed as higher cortical control develops.

In certain neurological conditions, however, some primitive patterns can re-emerge in adulthood.

These are sometimes described as frontal release signs because their appearance can reflect disruption of the higher cortical inhibition that would normally suppress these responses.

Examples discussed in the presentation include the grasp reflex, snout reflex and glabellar reflex.

The presentation also discusses the Babinski sign in the context of pathological neurological findings.

These findings have a very different meaning in adults than primitive reflex activity has in a newborn.

In an infant, certain reflexes represent normal development.

In an adult, their appearance or reappearance can be a clinical sign that warrants neurological investigation.

Primitive and Pathological Reflexes: An Interesting Connection

One of the most interesting concepts in the presentation is the connection between primitive reflexes during development and pathological reflex patterns later in life.

Both illustrate the relationship between higher cortical control and lower subcortical reflex circuits.

In infancy, higher cortical control has not yet fully matured.

With certain acquired neurological diseases or injuries, that previously established inhibitory control can become disrupted.

The outward circumstances are very different, but both demonstrate an important principle:

Healthy neurological function depends not only on the brain’s ability to activate movement, but also on its ability to regulate and inhibit automatic responses.

Why This Matters in Neurodegenerative Conditions

The re-emergence of certain primitive or frontal release signs can sometimes be observed in neurological conditions affecting cortical function.

For that reason, reflex testing remains one component of a neurological examination.

Hope Brain & Body Recovery Center works with patients experiencing conditions including Parkinson’s disease, dementia and other progressive neurological disorders through its Neurodegenerative Disorders program.

These conditions require comprehensive evaluation because changes in movement, cognition, attention, coordination and behavior can have many possible causes.

A reflex finding should therefore always be interpreted within the context of the person’s overall neurological picture.

Reflexes as a Developmental Roadmap

Perhaps the most useful way to think about primitive reflexes is as part of a developmental roadmap.

Their appearance tells us something.

Their integration tells us something.

Their persistence may tell us something.

And their pathological reappearance later in life can tell us something very different.

From the automatic grasp of a newborn to the skilled, intentional movement of an adult, human development represents a remarkable transition from predominantly reflexive responses toward increasingly sophisticated cortical control.

The presentation describes this beautifully as movement from survival to mastery.

The Sensorimotor Foundation of Development

Walking, writing, catching a ball or tying a shoelace may feel effortless to an adult, but each represents an extraordinarily complex neurological achievement.

The brain must process sensory information, understand where the body is in space, plan an action, activate the appropriate muscles, inhibit unnecessary movement and continuously adjust the response.

Primitive reflexes represent some of the earliest building blocks in this progression.

As the nervous system matures, increasingly sophisticated voluntary movements are constructed upon that early sensorimotor foundation.

This is also why neurological rehabilitation often considers much more than muscle strength alone.

Brain function, sensory processing, balance, eye movements, coordination and motor control all interact.

Hope Brain & Body Recovery Center’s broader approach to neurological rehabilitation focuses on understanding these interconnected systems rather than viewing neurological symptoms in isolation.

When Should Parents Consider an Evaluation?

No single developmental quirk necessarily means something is wrong.

Children develop at different rates, and neurological development is complex.

However, persistent concerns involving combinations of movement, coordination, balance, sensory processing, attention, learning or developmental milestones may justify a more comprehensive assessment.

The goal should not simply be to attach another label to a child.

It should be to understand how that child’s nervous system is functioning and determine whether specific areas may benefit from support.

Early identification can provide families and clinicians with more information and more opportunities to develop an individualized strategy.

From Automatic Survival to Human Potential

Primitive reflexes remind us just how extraordinary neurological development really is.

A newborn enters the world equipped with automatic responses designed to support survival.

As the brain matures, higher cortical networks increasingly regulate those responses.

Automatic grasping becomes intentional reaching.

Reflexive movement becomes coordinated movement.

And gradually, the child develops the neurological control required to explore, learn, communicate and interact independently with the world.

Reflexes, therefore, represent much more than the movements clinicians test during an examination.

They provide clues to the architecture of the nervous system itself.

Concerned About Your Child’s Neurological Development?

If your child is experiencing persistent challenges with coordination, balance, attention, sensory processing, learning or other areas of development, a comprehensive neurological assessment may help provide a clearer picture of how their nervous system is functioning.

At Hope Brain & Body Recovery Center, our team evaluates neurological function as part of a personalized approach to neurodevelopment and rehabilitation.

👉 Schedule a FREE consultation with Hope Brain & Body Recovery Center to speak with our team and learn whether a more comprehensive neurological evaluation may be appropriate.